The range of an object can be determined by ranging techniques involving the reflection of light from the object, with the range determination based on parallax, interferometry, or light time of flight. Parallax techniques require a long precision reference base line to obtain high accuracy, and require demanding image feature correlation processing to enable automatic range determination. Interferometric devices provide micron-level accuracy, but are very sensitive to disturbances and are complicated. Time of flight devices, wherein the time required for return of a light pulse directed at the object, have been limited in accuracy by the difficulty of constructing very high frequency precision counters and very fast and repeatable detectors. A ranging system which could provide automatic and precise ranging in a relatively simple and rugged apparatus, would be of considerable value.